Add last_requested field to the favicon_bitmaps table of the favicons database.

components/history/core/browser/thumbnail_database.cc

Index: components/history/core/browser/thumbnail_database.cc
diff --git a/components/history/core/browser/thumbnail_database.cc b/components/history/core/browser/thumbnail_database.cc
index e82888492a36db72869d5b2fc5544556922ceaa8..274350f4dd010880b26b4d2646ef7991b5c9d574 100644
--- a/components/history/core/browser/thumbnail_database.cc
+++ b/components/history/core/browser/thumbnail_database.cc
@@ -58,14 +58,17 @@ namespace history {
 //                    the |id| field in the appropriate row in the |favicons|
 //                    table.
 //
-//  id                Unique ID.
-//  icon_id           The ID of the favicon that the bitmap is associated to.
-//  last_updated      The time at which this favicon was inserted into the
+//   id               Unique ID.
+//   icon_id          The ID of the favicon that the bitmap is associated to.
+//   last_updated     The time at which this favicon was inserted into the
 //                    table. This is used to determine if it needs to be
 //                    redownloaded from the web.
-//  image_data        PNG encoded data of the favicon.
-//  width             Pixel width of |image_data|.
-//  height            Pixel height of |image_data|.
+//   last_requested   The time at which this bitmap was last requested. This is
+//                    used to determine the priority with which the bitmap
+//                    should be retained on cleanup.
+//   image_data       PNG encoded data of the favicon.
+//   width            Pixel width of |image_data|.
+//   height           Pixel height of |image_data|.
 
 namespace {
 
@@ -77,18 +80,19 @@ namespace {
 // fatal (in fact, very old data may be expired immediately at startup
 // anyhow).
 
+// Version 8: ???????? by rogerm@chromium.org on 2015-??-??
 // Version 7: 911a634d/r209424 by qsr@chromium.org on 2013-07-01
 // Version 6: 610f923b/r152367 by pkotwicz@chromium.org on 2012-08-20
-// Version 5: e2ee8ae9/r105004 by groby@chromium.org on 2011-10-12
+// Version 5: e2ee8ae9/r105004 by groby@chromium.org on 2011-10-12 (deprecated)

[Scott Hess - ex-Googler, 2015/03/19 21:32:22]

Cool beans.  I was going to suggest that earlier, but it seemed mostly unrelated
to this CL.  Certainly fine with doing maintenance as you go, though :-).

[Roger McFarlane (Chromium), 2015/03/20 14:40:59]

With they way recovery/upgrade is done, it was messy to support 5. So, this
wasn't *only* maintenance/cleanup.

:)

 // Version 4: 5f104d76/r77288 by sky@chromium.org on 2011-03-08 (deprecated)
 // Version 3: 09911bf3/r15 by initial.commit on 2008-07-26 (deprecated)
 
 // Version number of the database.
 // NOTE(shess): When changing the version, add a new golden file for
 // the new version and a test to verify that Init() works with it.
-const int kCurrentVersionNumber = 7;
-const int kCompatibleVersionNumber = 7;
-const int kDeprecatedVersionNumber = 4;  // and earlier.
+const int kCurrentVersionNumber = 8;
+const int kCompatibleVersionNumber = 8;
+const int kDeprecatedVersionNumber = 5;  // and earlier.
 
 void FillIconMapping(const sql::Statement& statement,
                      const GURL& page_url,
@@ -310,7 +314,10 @@ bool InitTables(sql::Connection* db) {
       "last_updated INTEGER DEFAULT 0,"
       "image_data BLOB,"
       "width INTEGER DEFAULT 0,"
-      "height INTEGER DEFAULT 0"
+      "height INTEGER DEFAULT 0,"
+      // This field is at the end so that fresh tables and migrated tables have
+      // the same layout.
+      "last_requested INTEGER DEFAULT 0"
       ")";
   if (!db->Execute(kFaviconBitmapsSql))
     return false;
@@ -396,7 +403,7 @@ void RecoverDatabaseOrRaze(sql::Connection* db, const base::FilePath& db_path) {
   // NOTE(shess): This code is currently specific to the version
   // number.  I am working on simplifying things to loosen the
   // dependency, meanwhile contact me if you need to bump the version.
-  DCHECK_EQ(7, kCurrentVersionNumber);
+  DCHECK_EQ(8, kCurrentVersionNumber);
 
   // TODO(shess): Reset back after?
   db->reset_error_callback();
@@ -448,9 +455,8 @@ void RecoverDatabaseOrRaze(sql::Connection* db, const base::FilePath& db_path) {
     return;
   }
 
-  // Earlier versions have been handled or deprecated, later versions should be
-  // impossible.
-  if (version != 7) {
+  // Earlier versions have been handled or deprecated.
+  if (version < 7) {
     sql::Recovery::Unrecoverable(recovery.Pass());
     RecordRecoveryEvent(RECOVERY_EVENT_FAILED_META_WRONG_VERSION);
     return;
@@ -613,11 +619,24 @@ sql::InitStatus ThumbnailDatabase::Init(const base::FilePath& db_name) {
 }
 
 void ThumbnailDatabase::ComputeDatabaseMetrics() {
-  sql::Statement favicon_count(
-      db_.GetCachedStatement(SQL_FROM_HERE, "SELECT COUNT(*) FROM favicons"));
-  UMA_HISTOGRAM_COUNTS_10000(
-      "History.NumFaviconsInDB",
-      favicon_count.Step() ? favicon_count.ColumnInt(0) : 0);
+  // Count all icon files referenced by the DB.
+  {
+    sql::Statement favicon_count(
+        db_.GetCachedStatement(SQL_FROM_HERE, "SELECT COUNT(*) FROM favicons"));
+    UMA_HISTOGRAM_COUNTS_10000(
+        "History.NumFaviconsInDB",
+        favicon_count.Step() ? favicon_count.ColumnInt(0) : 0);
+  }
+
+  // Count all bitmap resources cached in the DB.
+  {
+    sql::Statement bitmap_count(
+        db_.GetCachedStatement(
+            SQL_FROM_HERE, "SELECT COUNT(*) FROM favicon_bitmaps"));
+    UMA_HISTOGRAM_COUNTS_10000(
+        "History.NumBitmapsInDB",
+        bitmap_count.Step() ? bitmap_count.ColumnInt(0) : 0);
+  }
 }
 
 void ThumbnailDatabase::BeginTransaction() {
@@ -727,6 +746,22 @@ bool ThumbnailDatabase::GetFaviconBitmap(
   return true;
 }
 
+bool ThumbnailDatabase::GetFaviconBitmapLastRequestedTime(
+    FaviconBitmapID bitmap_id,
+    base::Time* last_requested) {
+  DCHECK(bitmap_id);
+  DCHECK(last_requested);
+  sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
+      "SELECT last_requested FROM favicon_bitmaps WHERE id=?"));
+  statement.BindInt64(0, bitmap_id);
+
+  if (!statement.Step())
+    return false;
+
+  *last_requested = base::Time::FromInternalValue(statement.ColumnInt64(0));
+  return true;
+}
+
 FaviconBitmapID ThumbnailDatabase::AddFaviconBitmap(
     favicon_base::FaviconID icon_id,
     const scoped_refptr<base::RefCountedMemory>& icon_data,
@@ -782,6 +817,17 @@ bool ThumbnailDatabase::SetFaviconBitmapLastUpdateTime(
   return statement.Run();
 }
 
+bool ThumbnailDatabase::SetFaviconBitmapLastRequestedTime(
+    FaviconBitmapID bitmap_id,
+    base::Time time) {
+  DCHECK(bitmap_id);
+  sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
+      "UPDATE favicon_bitmaps SET last_requested=? WHERE id=?"));
+  statement.BindInt64(0, time.ToInternalValue());
+  statement.BindInt64(1, bitmap_id);
+  return statement.Run();
+}
+
 bool ThumbnailDatabase::DeleteFaviconBitmap(FaviconBitmapID bitmap_id) {
   sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
       "DELETE FROM favicon_bitmaps WHERE id=?"));
@@ -1086,6 +1132,8 @@ bool ThumbnailDatabase::RetainDataForPageUrls(
       "ON (old.id = mapping.old_icon_id)";
   const char kDropOldFaviconsTable[] = "DROP TABLE old_favicons";
 
+  // Note that we allow the last_requested field to be reset to the default
+  // value (0).
   const char kRenameFaviconBitmapsTable[] =
       "ALTER TABLE favicon_bitmaps RENAME TO old_favicon_bitmaps";
   const char kCopyFaviconBitmaps[] =
@@ -1194,7 +1242,7 @@ sql::InitStatus ThumbnailDatabase::InitImpl(const base::FilePath& db_name) {
 #endif
 
   // thumbnails table has been obsolete for a long time, remove any

[huangs, 2015/03/19 19:14:11]

NIT: unwrap?

[beaudoin, 2015/03/19 21:36:54]

I'm fine leaving it wrapped, 90% of the multi-line comments in this file could
be unwrapped. It would almost look off if this one was. :)

[Roger McFarlane (Chromium), 2015/03/20 14:41:00]

Acknowledged.

[Roger McFarlane (Chromium), 2015/03/20 14:41:00]

Done.

-  // detrious.
+  // detritus.
   ignore_result(db_.Execute("DROP TABLE IF EXISTS thumbnails"));
 
   // At some point, operations involving temporary tables weren't done
@@ -1252,6 +1300,12 @@ sql::InitStatus ThumbnailDatabase::InitImpl(const base::FilePath& db_name) {
       return CantUpgradeToVersion(cur_version);
   }
 
+  if (cur_version == 7) {
+    ++cur_version;
+    if (!UpgradeToVersion8())
+      return CantUpgradeToVersion(cur_version);
+  }
+
   LOG_IF(WARNING, cur_version < kCurrentVersionNumber) <<
       "Thumbnail database version " << cur_version << " is too old to handle.";
 
@@ -1332,6 +1386,19 @@ bool ThumbnailDatabase::UpgradeToVersion7() {
   return true;
 }
 
+bool ThumbnailDatabase::UpgradeToVersion8() {
+  // Add the last_requested column to the favicon_bitmaps table.
+  const char kFaviconBitmapsAddLastRequestedSql[] =
+      "ALTER TABLE favicon_bitmaps ADD COLUMN last_requested INTEGER DEFAULT 0";
+  if (!db_.Execute(kFaviconBitmapsAddLastRequestedSql))
+    return false;
+
+

[huangs, 2015/03/19 19:14:11]

NIT: extra space.  I recently learned about "git cl lint", maybe try that?

[Roger McFarlane (Chromium), 2015/03/20 14:41:00]

Done.

+  meta_table_.SetVersionNumber(8);
+  meta_table_.SetCompatibleVersionNumber(std::min(8, kCompatibleVersionNumber));
+  return true;
+}
+
 bool ThumbnailDatabase::IsFaviconDBStructureIncorrect() {
   return !db_.IsSQLValid("SELECT id, url, icon_type FROM favicons");
 }